American hops have been used in English brewing since the mid-1800's at least. They were mixed with English hops (and sometimes other importations), always in a much lesser proportion to English crops, because they were felt too oddly flavored, "rank" is a term often encountered. Here are two references, 12 years apart, to the piney taste of American hops as viewed by English brewers circa-1850:

When I first started tasting American microbrewed beers I was struck by a taste I called piney or fir-like or resin-like. While not all American hop varieties are the same of course, the classic "c-hops" (which include Cascade and Centennial) often seem to have this taste. It is today an emblem of fine U.S. microbrewing yet is not always appreciated elsewhere (or in the States by some for that matter). Liberty Ale from Anchor is a progenitor of this style. In the past (pre-micro era), blends of American hops and sometimes imported hops were used in quantities much smaller than are often used for micro pale ales and IPAs, and I wonder if it wasn't to downplay this characteristic taste. In the first link above, clearly the brewers thought pine wood was actually used to dry the hops (hence the concern about their "management") but in the second link, from 1857, it is clear that the English realize this is an inherent characteristic of the hops.

What I find striking about these old discussions is that nothing really has changed since then. U.S. hops do (most of them I think) still have this piney taste - they did then and they do now and that must be, as discussed in the 1857 hearings, the result of the particular soils and climate in the U.S. Foreign varieties are often grown yet the characteristic taste often results. And contrarily, English hops are still, the best of them, grown in East Kent in the south and probably always had their characteristic flowery/earthy/lemony taste. There is no question that fine brewing exists in both places, so much depends on how a brewer handles the materials he has even assuming he restricts to domestic types, yet overall I think that micro U.S. and Canadian pale ales and IPAs tend to present the kind of piney palate noted in the U.K. in the mid-19th century. The English Goldings and other varieties discussed in the 1857 hearings surely were again likely very similar to today's English types.

So often we discuss whether a flavor of today existed 150 years ago and how can we ever tell if it did? Well here is tangible proof that we can - sometimes.